Olympians' lives are measured in four-year increments. For sabre fencer Keeth Smart, each quadrennium's passing has come with major life changes. Approaching his third Olympics, he found this interval to be the most challenging of all, and revealed that Beijing will likely be the last Games in which the public will see one of America's finest sabre fencers wield his sword.

For Keeth and his younger sister, Erinn, "fencing" and "family" have been synonymous since the day in the late 1980's or early 1990's when their father, Thomas, asked his colleagues at Sports Illustrated which sport would help his children get into a good university.

The reply was fencing, and his children excelled. By junior high, they were competing nationally, and in high school, they were competing abroad. Keeth was accepted at St. John's and Erinn attended Barnard College, both in New York City.

In 2000, when Keeth was 22, he made the Olympic team in the individual sabre event while Erinn, then 20, was a non-playing alternate in team foil. Having one child compete while the other one sat idle tore at their mother, Liz, who was her children's biggest fan, chauffeur, financier, and - in times like this, source of consolation.

After placing 30th in Sydney, Keeth graduated from St. John's in 2001 and had to adjust to post-college fencing.

"Being a coddled athlete was no longer an option," he said. "I had to find my own path."

He took a year off and worked in finance at Verizon. In 2002, he returned to fencing and placed 10th individually at that year's World Championships - his best solo effort at a Worlds or Olympics to date. In 2003, he made history by becoming the first American to be ranked No.1 in the world.

Although Keeth's ranking slipped before the Games, he was the clear leader of U.S. men's squad, and team sabre proved to be one of the most dramatic fencing events in Athens.

In the quarterfinals, the U.S. upset the No.3 seed, Hungary, to earn a semifinal berth against France. In the round-robin format, the strongest fencers competed last. With the U.S. trailing France, 40-38, Smart rallied to a 44-44 tie. One point from victory, Smart's sword pierced his opponent's glove. During the injury time out, Keeth turned to Erinn (who made the women's team) and his mother in the stands. He smiled and nodded to let them know he was in control. The Frenchman returned, bandaged and bloodied, and the next few touches were ruled to be simultaneous. And in a final close call, the referee awarded the victory to France. The U.S. would not be guaranteed gold or silver. It would have to fight for the bronze.

"Keeth was extremely upset," recalled U.S. Olympic coach Yury Gelman. "He completely got [robbed]. We couldn't officially protest because it's our eyes and the ref's eyes, and the ref always wins this war. We don't think it was done purposely, but you never really know."

A few hours later, the U.S. faced Russia in the bronze-medal match. A victory would have given the U.S. its first men's Olympic fencing medal in 20 years. The U.S. was leading, and was up to Smart to earn the last five touches. Smart earned four and, once again, the U.S. lost by one point. Russia captured the bronze, the U.S. finished fourth, and France - the Americans' spoiler - beat Italy in the gold-medal match.

After the loss, Smart was visibly devastated, shaking and sobbing. His mother and sister were in tears, too. Even though it was a remarkable finish, Smart felt he let down the team.

"After Athens, I fell into a depression," he said. "Maybe not clinically diagnosed, but it was such a heartbreaker to lose two opportunities for a medal, back-to-back."

He barely fenced at all in 2005, and focused on work. Then, in August, Erinn called with some horrendous news. Their father had suffered a fatal heart attack during his morning jog.

This time, in his distress, Smart sought solace in the one place he felt most familiar and comfortable: under a mask with a sword in his hand. Fencing, he said, "Kept my mind from dwelling on the loss of my dad."

In 2006, his world took another bad turn. His mother's colon cancer had metastasized. When it was first diagnosed, in 2000, she scheduled her chemotherapy so she could travel to Sydney. It returned before Athens, and she beat it again. This time, she was given six months to live, and beat it -not literally - but in her own way. She made it to Keeth's wedding, in May 2007. She made it to the 2007 Nationals, in Miami, where Erinn was vying for another U.S. title. Liz Smart sat there all day, till 11pm, even though Erinn said it was OK to go. She said, "No, I want to watch."

Erinn said, "She looked healthy on the outside, but inside, she was fighting."

Between tournaments, Keeth flew to Florida to help his "ultimate fencing fan" the way she had supported him for so many years

Finally, on May 25, 2008, Liz Smart passed away at age 55.

At the funeral, fencers showed up en masse. Olympic coaches and teammates gathered around Keeth and Erinn, the children Liz raised to be as close as twins.

Tim Morehouse, who had known the family since he was 13 and will compete with Keeth in Beijing said, "I think we all knew. If anything happens, we'd help them."

As Keeth contemplated his future without its foundations, the blood disorder he had contracted in April was quickly forgotten. The left-thumb ligament tear he endured in February, fell away. The business school applications were in and he knew where he was going after Beijing: Columbia University. And then, something mysterious happened; Keeth started fencing really well again.

He will enter Beijing ranked No. 5 in the world - his best rank going into an Olympic Games. All year, he had used fencing to relieve stress, and one day in mid-July, he sat down after training in Manhattan and said, "I love coming to practice more than anything now, because it's the one constant in my life."

Asked whether he might continue after Beijing, he said, "I think it's time to stop."

After the interview, Keeth boarded a train to Brooklyn, got off, and walked up to the building where his whole family had lived. He was moving to Harlem that evening so he would be closer to school when the Games were over.

The next night, by phone, Erinn revealed that she, too, would be done after Beijing. Her fencing life and family life that were so intertwined would branch into a new direction. Her parents were gone, and her brother had left.

And when the call came to an end, she hung up the phone in Keeth's old place and finished sweeping and mopping his now-empty space.

Aimee Berg is a freelance contributor for teamusa.org. This story was not subject to the approval of the United States Olympic Committee or any National Governing Bodies.